Abstract : Viscous and thermal losses of acoustic energy at a metal wall are calculated for the condition in which there is a low Mach number flow sustaining a temperature difference between the gas and the wall. The acoustic loss is found to decrease as the walls are cooled below the temperature of the main body of the gas. The results of the study are relevant to experiments on acoustic amplification by solid rocket propellants and to at least some cases of liquid propellant rocket acoustic instability. (Author)